Percussive tool appliance



Aug. 8, 1950 w. H. MOORHEAD PERCUSSIVE TOOL APPLIANCE Filed Sepd. 27, 1946 INVENTOR.

Patented Aug. 8, 1950' 1 I UNITED v STATES PATENT OFFICE I 2 2,518,429 2 it PERQUSSIVE Tool. APPLIANCE Walter H. Moorhead, South Euclid, Ohio Application September 27, 1946, Serial No. 699,912

My invention pertains to a percussion tool and more particularly to an appliance for rotatingand for intermittently reciprocating in an axial direction, a tool carried thereby.

I have satisfied myself that my relatively somewhat modified models perform in an improved manner, especially in small and light sizes suitable for convenient manipulation in their entirety and carrying cemented-carbide tools-provided speed of rotation and rapidity, force and distance of axial strokes have been most effectively correlated as empirically deter mined. An attainment of that desideratum has accordingly constituted my primary object.

ure 1, looking in the direction of the indicating arrows.

Figure 3 is a 'view corresponding to Figure l of a modified form of my origination.

Figure 4 is a radial section on line 44 of Figure 3 viewed as directed by the section-line arrows.

A tubular housing I fixedly encloses, consequent to the common expedient of a pressed or shrunk fit therebetween, (or slidably encloses if in splined connection) a thicker tubular member 2 which occupies only a middle section of the housing. One end face of the tubular member, cam cylinder or hammer 2 is fashioned, as exemplified, as a double-action cam comprising semi-annular convolute-sections of a helix, marked by the numerals 3 and 4 respectively and further comprising, each, an abrupt shoulder defined by a surface in a near-axial plane. Such shoulders 5 and 6 are diametrically opposite as may be observed in Figure 2. While I have experimentally come to prefer a double cam, a single or other multiple circumferential arrangement are alike feasible and have been manufactured and used. At its end which carries the cam, the interior tube '2 is provided with a bore 1 adapted to serve as one bearing for a central shaft 8. At its opposite end the tubular member 2 is formed with a comparatively larger bore 9,

5 Claims. (01. 74- 56) CPU . function or axial throw of the cam and of the to provide, in the radial plane where the bores i and 9 communicate with each other, an annular shoulder l0 serving as an abutment for one end of a compression, coil spring which envelops the shaft 8. An anti-friction bearing i2 011 the shaft 8 abuts the other end of the spring H and the spring may be'maintained in compression by la slotted, spring-clip l3 which is cheaper and more expeditious of attachment or removal than'would 1 be a nut cooperating with a threaded section of the shaft. Beyond the clip l3, the shaft is shown to be of slightly reduced size for connection with a common clutch provided on flexible driving members. The other end of the shaft 8 may, for

I instance, be integrally formed as a tool chuck l5 16 for comprising the conventional set-screw clamping the shank of any chosen tool (not shown) and also including an enlargement l1 fitted within the housing I. Eccentrically, the

interior end of the enlargement I1 is supplied tact with the cam by the action of the spring H whereby, twice during each rotation of the shaft 8, it successively travels along one or the other of the two shoulders -5 and 6 thereby furnishing an adjustable control for wear during the release shaft whereby to deliver a forward impulse to chuck and the tool.

The form hitherto described causes the handle-serving housing, when the appliance is in power-driven operation, to impart negligible hand tremors consequent to its reciprocation along with the tool. In the modified form next to be differentiated, a simple arrangement eliminates, not the slight and endurable vibration, but the positive reciprocation of the housing which is to be grasped by the hand. In the modification of Figure 3, the housing 2| may be exteriorly supplied with knurling (not shown, because long a common expedient to insure a firmer grip), but is definitely formed with an interior channel 22 extending parallel with the axis. The cam-bearing tube 23 is similarly formed with a complementary and registering channel 24. A key 25 occupies sections of said channels and while insuring the relative movement in an axial direction as between the tube 23 and the housing 2! whereby to be somewhat more comfortable, involves an added cost of manufacture.

Upon future consideration, it is to be realized that the scope of my invention, as defined by the claims, comprehends equivalent constructions involving the same principle of operation and that the showing of the drawings and the specific description thereof are intended merely to exemplify a plurality of mechanical embodiments and arrangements.

For instance, the inner tube 2 or hammer might turn with the shaft and the cam-engaging finger be not rotatable whereby to achieve an equivalent mere reversal. Nor need the cam be on an end' of the inner tube 2, because, though more complicated and expensive, it might be be,- tween its ends and. the shaft carry the finger at a suitable place so as to ride thereoven I claim:

1. In an appliance of the character described, the combination of a housing, a cam. cylinder locked against turning movement interiorly thereof, a shaft mounted in said cylinder for-bothturning and axial movement relatively thereto, a driving connection for rotating: said; shaft, a coil. spring within said cylinder and arotmd said shaft for actuating the latter axially and: means comprising a cam for controlling. the axial. more ment of said shaft; said cam-beingformed with an abrupt, axially alined'. shoulder surface; adapted suddenly to; permit. the axial travel of. said shaft in one direction in response. toath'e ac.- tion of said spring;

2. In combination, hcllow handle, an". antifriction beari-ngi therein, a cylinder secured? against turning movement. therein and. provided! with axial bores ofdiiferent diameter at: its opposite ends respectively, one end of said: cylimder being fashioned as an arcuate cam, a: struc ture comprising chuck and; rotatably mounted in said cylinder and; withone end in: appcsiti'en to one: end of said? cylinder and carrying a pro.- jection adapted: to engage. and travel: around said cam, said structure: further comprising a shaft mounted near one of its: ends. in: cylirider and near its other end in said bearing andi a; compression spring around saildishaft 'anidlwith its end's abutting an end ofsaid'i cylinder said. bearing respectively.

3; In combination, a tubular structure. having ends of varying thickness; the end ofgreater thickness. being fashioned 'as'. an annular cam, another structure rotatably mounted in said tu bular structure and having a-chuck-forming end,

an axially adjustable wear-finger mounted on said chuck and adapted to cooperate with said cam whereby to permit the release throw of said rotatable structure, the latter including a shaft, a compression spring around said shaft and within said tubular structure and means for maintaining said spring in compression.

4. In combination, a housing, a shaft rotatably and reciprocably mounted in said housing and projecting from both ends thereof, a cam structure carried internally by said housing, the latter being also formed with an annular shoulder, a cam-engaging finger eccentrically carried by one end of said shaft, a coil spring around a part of said shaft and abutting said shoulder and means for holding said spring in compression, said cam structure comprising a plurality of circumferentially spaced crests terminating at planes extending in the same general direction as the axis to define abrupt shoulders whereby successively to: deliver sudden impacts during each rotatihn.

5; Inv combination, a. composite housing; a cylinderneciprocable: in. said. housing and including. a cam surface, a. shaftmonnted; in one. end. of. said cylinder for rotatable: and axially slidable movement, a; spring? around said; shaft; and occupying the other end of said; cylinder for. urging the latter axially and. a structure. adjustabl'y carried. by said shaft; and. adapted. to engage: the: cam surface. on: said cylinder successively to.- retract said shaft against the action. of said. spring.

- WALTER; MOORHEAII.

REFERENCES. CITED;

The following references are of recordin the file of this patent:-

STATES PA'I'ENTIS' Germang- July 25-, 1 9.11. 

